This invention relates to apparatus and method for providing information on the condition of the heart muscle, particularly during post-operative care following open heart surgery. It has been determined that the endocardial viability ratio is related to a heart condition of significant interest. See the article in Circulation Research Volume XXX, January 1972, pages 67-81, Experimental Subendocardial Ischemia in Dogs with Normal Coronary Arteries, by Buckberg et al. In the work described in the article, certain conditions were produced in the heart, measurements were taken and recorded, various calculations were then made to obtain various data including the endocardial viability ratio (EVR), the muscle was examined, and the conclusions were drawn relating muscle condition to EVR.
This is a time-consuming and laborious process, and it is an object of the present invention to provide a new and improved apparatus and method for obtaining the EVR instantaneously and continuously so that heart conditions can be monitored and appropriate procedures initiated as required.